Magnetic mounting device for gun sights



Nov. 7, 1961 K. R. DETRlcH 3,007,248

MAGNETIC MOUNTING DEVICE FOR GUN SIGHTS Filed Sept. 5, 1958 `FIGURE 3 is` a portion of the mounting device cut away.

JUnited States SDEVICE FR This invention relates to a mounting device for telescopic gun sights, and more particularly to a mounting :device which utilizes the magnetic force of permanent 'magnets as the sole means for holding the telescopic sight in'its proper position on the gun.

Another object of this invention is to provide a mount- -ing device for telescopicv sights which permits rapid removal and replacement of the sight without affecting a .preset alignment of the sight with the bore of the gun. .f A still further object of this invention is to construct Aa magnetic mounting device for gun sights that will permit the sight to becomedislodged from its operative position on the gun should the sight receive a severe jolt, as by rough usage, thus avoiding possible 'damage to the sight or causing it to become misaligned with the bore vof the gun when replaced in its operative position.

`A still further object of this invention is the provision of a mounting device for telescopic gun sights which requires a minimum of time and skill in the preparation of the gun for receiving the mounting device.

A still further object of this invention is to provide a magnetic mounting device for gun sights with a built in keeper for protecting the magnets against loss of residual :magnetismwhen the sight is not in position on the gun.

Another object is to provide a means for securing a telescopic sight to a device for mounting the sight on a gun, which means is in the nature of a semi-universal joint to facilitate adjustment of the sight to a position in alignment with the bore of the gun.

Another object is to provide a magnetic mounting device of the type described which includes a keeper to protect against loss of magnetism and which also utilizes a separator strip of non-magnetic material between the keeper and permanent magnet for reducing the strength of the magnet when not in use to protect against adherence of foreign particles thereto.

A still further object is to provide a gun sight mounting device that has suicient magnetic attraction to retain the same on a gun during normal use of the gun but which is quickly and easily removable from the gun by pulling it with the hand. Another object is to provide a mounting device of the .type described in which a permanent magnet is retained in position adjacent the upper end of a pair of pole pieces by a block of non-magnetic material xed to said .p'ole pieces.

Another object is to provide a magnetic mounting de- Vvice for gun sights in which magnet and pole pieces of substantially the same width are employed whereby a ilux path of minimum reluctance is established when the pole piece is in position on the gun.

Other objects will be apparent from the following description and from the drawings in which:

FIGURE 1 is a side View showing a telescopic sight mounted on a gun by means of the magnetic mounting device comprising the present invention, the gun being 'fragmentarily shown.

FIGURE 2 is an enlarged end view of the mounting device and a fragmentary portion of the telescopic sight and gun.

side view of FIGURE 2 showing a atent FIGURE 4 isa cross sectional view taken on line FIGURE 5 is a diagrammatical view, illustrating the principal magnetic circuit when the sight is mounted on the gun.

` FIGURE 6 is a diagrammatical view illustrating the principal magnetic circuit when the sight is removed from the gun.

The telescopic sight 10 illustrated in FIGURE 1 is of a conventional telescope type and has a cylindrical tube 11 secured substantially in parallelism with the bore through the barrel or receiver 12 of a gun by a pair of identical magnetic mounting devices 13 which comprise the present invention. Since the mounting devices are identical, the following description is confined to one but is applicable to both.

The magnetic components of the mounting device, which comprise a magnet assembly, consist of a keeper 14 of magnetic material, a separator plate 15 of nonferrous material, a retaining block 16 of hard non-magnetic material, a permanent magnet 17 and a pair of soft magnetic steel pole pieces 18. v,

To retain the keeper 14, separator plate 15, and'pole pieces 18 in assembled position, a pair of non-magnetic retainer plates 20 are silver soldered to the keeper and the pole pieces. The permanent magnet 17 is retained in position by the retaining block 16 -which is pinned to the pole pieces by roll pins 21.

The keeper 14, separator plate 15, permanent magnet 17, and retaining block 16 have aligned bores 23, Z4, 2S, and 26 therethrough, respectively. A non-magnetic bushing 27 is located within the bores and is held in position by silver soldering to the keeper 14. The bushing has an internal thread 28 therethrough into which is threaded a non-magnetic centering pin 29 having a tapered extension 30. The pin 29 has a drilled hole 31 therethrough and a screw driver slot 32 at one end.

The pole pieces 18 have arcuate openings 34 formed on their under sides for intimately tting'and contacting the curved surface of the gun barrel upon which the device is to be mounted. The lower side of the retaining block 16 is likewise arcuately formed as at 35 but at a slightly larger radius than the arcuate portion of the pole faces so that there is a small space 36 between the retaining `block and the gun barrel 12 when the mounting device is in position on the gun.

The upper side of the keeper 14 is arcuate as viewed in FIGURE 2 and has a groove or channel 40 therein which in cross section is formed on a radius 41 which is preferably in the neighborhood of twice the diameter of curvature of the arcuate upper side of the keeper. On each side` of the groove 40 there are short cylindrical portions 42.

Fitted within the groove 40 is a ring 43 having a longitudinal split 44. The outer surface of the ring is curved in cross section -to the same radius 41 as the groove 40. The inner diameter of the ring is such as t0 l'it the outer diameter of `the telescopic sight 10. The ring 43` is'retained in position on the keeper by a strap 46 which has an arcuate portion 47 and radially extending portions 48. The arcuate portion 47 has a groove 49 corresponding .to the groove 40 in the keeper and which groove in cross section is formed to the same radius 41 for closely fitting the outer surface of the ring 43. The radial portions 48 overlie the side plates 20 and are secured thereagainst by screws 50 threaded into keeper 14. The ring 43 and strap 46 are so proportioned that tightening of the screws 50 causes the strap to compress the ring tightly against the telescopic sight for rmly clamping the same to the mounting device, it being understood that there is sulicient initial clearance between the radial portions 48 and the retainer plates 20 for this purpose.

By forming the outer surface of the ring and the complementary inner surfaces of the strap 46 and keeper 14 on radius which is approximately twice the diameter Y' of suchpsurfaces, a semi-universal swiveling action of the greatest aux' isY as aagrammatieauy illustrated in FI- ring 43 within the channel Vportions of the keeperV and strap is obtained when the sight is loosely held by thevr -two mounting devices when the latter are in position on barrel determined by 'the'tit of arcuate openingsV 34 of the pole face on the gun barrel and the fit of the tapered extension 30 ofthe pinV 29 in the tapered locating hole 52 in the gun barrel., When the two mounting devices are in such set posi-tions, if there is any misalignmentV of the longitudinal aXis of the ring 43 of the one device with Y magnetic flux therethrough so-'that the flux pathwill beY the longitudinal axis of the ring of the other device, the y rings will swivel as necessary within the respective straps 46 and keepers 14 so that their longitudinal axes will f become aligned and permit firm clamping ot the telescopic sight as the screws 50 are tightened. Y A

It has been found preferable to provide only the semiuniversal action afforded when the radius 41 is approxi- Vmately twice the diameter of Athe outer' surface ofthe ring since the clamping action on the sight is moreiirm 'and there is less tendency for the sight to swivel or shift within either of the devices when the gun'is tired or roughly handled.

T o prepare a gun for the mounting devices, the center-V ing pin 29 of each device is retracted so that the arcuate sections 34 of the pole pieces may rest tirnly'on the gun barrel. With the sight in position, the two devices 'are then aligned and properly located on the gun barrel. vWhen the proper location of each device has been determined, the straps 46 and rings 43 and thesight 11 may be removed and a drill or other suitable tool inserted through the drilled hole 31 tomark the center location for the tapered hole 52 to beformed in the gun barrel for each device. After the tapered hole has been formed, the mounting device is put back intoits' proper position and the centering pin 29 `is threaded toward the gun bar'- rel until the tapered extension 30 seats in the tapered hole '52. At such time the` tapered extension() Vand the arcuate openings 34 of both pole pieces for each mounting device will be in contact with the gun barrel and will effectively locate the mounting device inatilted` predetermined position. Since the pole pieces have relatively -little thickness the actual aeagof contact'with the gun barrel is relatively small and thus there is less chance that nicks orvforei'gn matter will cause improper seating of the pole piecesY against the gun barrel.

Aitor both tapered holes 52 have been formed,- and the mounting devices placed in position on 4the Vgun Ybarrel i with ythe centering pins 29'properly adjusted to seat in the tapered holes, the rings 43 may be slipped overthe 'telescopic sight 10 and Vplaced in position in the Vgroove 40 of the respective keeper 14. The straps 46'are ytheir placed in position and the screws Sil tightened toiirm'ly clamp the telescopic sightnontothe mounting devices.

Each mounting device is retained in its position von the gun barrel by magnetic attraction. Thus, as diagrampieces' with the gun barrel, the ux path shown in PIG- 'Y URE 5 is the one affording the least reluctance and hence and hence provides Ithe greatest amount of magnetic iluxY when the mounting device is in position.

The keeper is desirable Vfor preserving the residual` 'matieany illustra-tea in FIGURE 5, when the mounting URE 6V since the path of least reluctance is from the magnet 17 through the pole piece 18,` through'the nonmagnetic separator strip 15,*the keeper 14, the other pole piece 1S, and back to the magnet. Y

The separator strip acts as alsmall air gap which provides enough reluctance to ,canse` the magneticux to follow the path illustrated in -FIGURE 5 when the mounti ing device is in position with thepolefpiece incntet with the gun barrel, and yet 'permits 'passage ofthe as illustrated in FIGURE 6 when the mounting device is removed from the gun barrel and permits the'kec'per 14 to help retainthe residual magnetism of the magnet 17.

, The Vseparator strip also aiords a gradual tnsition Vtifs the flux pathl -fro'mthat shown in FIGURE 6 torthatofY Y FIGURE.Y 5 when placing the telescopic .sightjin 'positionV -on the gunand thus minimizes the snap actionrof thcmagnetas itf is attracted to the gun barrel when Vappoaclaring the same.VY This permits steadier andmore accurate placement of the sight infits proper position kcon theglmr Vand lessens the chance Yof nicking or damaging the prts.

Itwill be seen that with the-presentrinventionatelcscopic sight may be Yquickly attachedor reioved from t.

a gun.v To attach the same, Ythe telescopicv sight,V with the mounting devices iirmly'clamped theretoV aspreviously described, isV simply placed in position on the-,gn

Ybarrel with the centering pins 29sseated Yin -thetapeed holes 52. Magnetic attractionrthenholds the mounting devices and the attached sight firmly inthe `preset fixedV position. To remove the sight, itis simply grasped by the hand and pulled 01T the gun barrel.

Although a preferred embodiment ofvv the r .ivfer'itionv has been illustrated and described, it is obvious that many changes maybe made in the detail constructionV without departing from the' invention as covered by the Vfxllovt'ir'igV claims.

I claim: j

l. A mounting device for gunsights comprising' a magnet assembly including afpermanent bar mgx'ietand it pole piece at each end of the magnet, lthe lower ends'f `said pole pieces being adapted to seatY on av gun and being shaped to engagev in intimate Contact therewith when in position on said gun so as to providel a-pth with said gun for magnetic ilux generated by Vsaid permanent magnet, means for attaching a gun sight vto said magnet asi sembly, said magnet being Vlocated between said ple pieces adjacent the upper ends thereof, said magnet ass sembly also. including'a retaining bloekof ncm-tiiagnetic4 material fixedV to said pole pieces adjacent the .lower ends thereof for retaining-'said permanentimagnetfiguggid assembly; ,Y

2. A mounting rdevice in aecofaaneefwith'entreprisfi Y Vwhich the lower end of saidretaining blclgiirspccd from said gun barrel when the device is in positionen s'aid barrel whereby nicks' and foreign matteronan between said vretaining block and barelwill not interfere with the .intiniatev contactofthe pole pieces saidY barrel;` v

3. A mounting l a ilux path of minimum relnctance'is established when magnetism when the device is removed from the gun Ato Y be stored over long periods of time.

When the mounting device' is removed `from the gun barrel, the path of the device ismounted on a gun barreLY 4. magneti'mou'nting deviceforgri sightscomprising a permanent magnet assembly, said seiiil'4 includingfa pair of`space`d pole pieces, a permanent mag-V Y Vnet between the upper ends ofsaid pole Ypieces,4 a separtorjplate ofnon-magnetic material above-said pole piecs and magnet; a keeper of -magrretematerial above said ieping block belowsaid magnetV and attached to the vlliiv'til' ends 0f Said pole' pieces' for retaining" said magietfwithin Y device in aeeordneev'vitii elainili- Vwhich. said magnet is of rectangular crossrsectidn'and Vofi substantially the same width of saidpolepieces whereby l l l said assembly, said pole pieces being shaped to seat on a gun barrel, and means for attaching a gun sight to said assembly.

5. A magnetic mounting device in accordance with claim 4 in which said keeper, separator plate, and retaining block have aligned openings therethrough, and means within said openings for locating said assembly in a predetermined position on said gun barrel.

6. A magnetic mounting device in accordance with claim 4 in which there is an adjustable means carried by said mounting device for cooperation with an opening carried by said gun barrel for adjustably locating said device on said gun barrel.

7. A magnetic mounting device in accordance with claim 4 in which said keeper, separatorplate, permanent magnet, and retaining block have aligned openings, a locating device within said openings, said locating device including an internally threaded bushing firmly attached to one of said parts having an opening, and a centering pin threaded into said bushing and having a portion projecting therefrom for reception within an opening carried by said gun barrel.

8. A device for attaching a sight to a firearm comprising a permanent magnet for attaching the device to the firearm by magnetic attraction, and a semi-universal joint for attaching the sight to said device, said joint including a circular split ring for surrounding the sight for clamping the same, said split ring having a convex outer surface, a concave arcuate surface on said device for receiving a portion of said ring, a member having a concave curved surface engageable with another portion of the ring and attached to said device for clamping said ring tightly about said sight, said concave surfaces in planes normal to the longitudinal axis of said device having a circularity corresponding to the circularity of said convex surface, all of said surfaces in planes parallel to said longitudinal axis being curved to a radius greater than the maximum radius of said circularity whereby a semi-universal connection between said device and sight is obtained in which said sight may be positioned with its axis at a selected angle with the axis of said device when said ring is loosely clamped by said member and in which said sight may be securely clamped in said selected position when said ring is tightly clamped by said member.

9. A device in accordance With claim 8 in which the radius of said curvature is substantially twice the maximum radius of said circularity.

References Cited in the file of this patent UNITED STATES PATENTS 2,306,972 Meisel Dec. 29, 1942 2,510,634 Hull June 6, 1950 2,535,791 Fluke Dec. 26, 1950 2,589,349 Diefenbach Mar. 18, 1952 2,782,509 Ivy Feb-l 26, 1957 2,857,675 Kesselring Oct. 28, 1958 2,861,344 Moore Nov. 25, 1958 2,911,723 Ashbrook Nov. 10, 1959 2,924,881 Gee Feb. 16, 1960 2,931,101 Martin Apr. 5, 1960 

